Heatsink fan structure

ABSTRACT

A heatsink fan structure includes an impeller having a hub provided with a pivot portion rotatably mounted on the pivot portion of the housing. The hub of the impeller has a periphery provided with multiple blades that are arranged in a radiating manner. A circular fixing frame is mounted on an outer periphery of the blades. The fixing frame has a permanent magnet. The upper and lower ends of each of the blades are not protruded from the fixing frame.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a heatsink fan structure, andmore particularly to a heatsink fan structure, wherein when the impellerof the heatsink fan structure is rotated, the wind shear noise producedbetween the impeller and the outer frame of the heatsink fan structuremay be reduced.

[0003] 2. Description of the Related Art

[0004] A first conventional heatsink fan structure in accordance withthe prior art shown in FIG. 8 comprises a housing 80 formed with areceiving space 81 for receiving a stator 82 which is wound with a coil.A rotor 83 has a rotation shaft 84 rotatably mounted on the stator 82.However, when the rotor 83 is rotated, a wind shear noise will producebetween the outer periphery of the blades 85 of the rotor 83 and theannular wall of the receiving space 81 of the housing 80.

[0005] A second conventional heatsink fan structure in accordance withthe prior art shown in FIGS. 9 and 10 is disclosed in the applicant'sTaiwanese Patent Publication No. 382412, comprising a base board 90having a shaft 91 for supporting an impeller 92 to rotate. The outerperiphery of the blades 93 of the impeller 92 is combined with a magnetring 94. The base board 90 is provided with multiple poles 95, and anouter frame 96 is mounted on the base board 90. The magnet ring 94 mayinduce with the poles 95 of the base board 90, so that the impeller 92may be rotated, and the blades 93 may drive the air to flow.

[0006] The magnet ring 94 of the conventional outer pole type heatsinkfan structure has a single thickness, and has a smaller height. Thus,when the magnet ring 94 is combined on the outer periphery of the blades93, the blades 93 are protruded from the upper and lower end of themagnet ring 94. Thus, when the heatsink fan is rotated, the airintroduced by the blades 93 cannot be driven toward a determineddirection efficiently, and will escape sideways from a position ofthickness difference formed by the distal ends of the blades 93 and theupper and lower end of the magnet ring 94. In addition, a wind shearnoise will produce between the sideward escaping air flow and theperipheral poles 95.

SUMMARY OF THE INVENTION

[0007] The primary objective of the present invention is to provide aheatsink fan structure, wherein when the impeller of the heatsink fanstructure is rotated, the air flow driven by the blades may be drivenalong the designed direction.

[0008] A secondary objective of the present invention is to provide aheatsink fan structure, wherein when the impeller of the heatsink fanstructure is rotated, the wind shear noise produced between the outerperiphery of the blades of the impeller and the housing of the heatsinkfan structure may be reduced.

[0009] In accordance with the present invention, there is provided aheatsink fan structure includes an impeller having a hub provided with apivot portion rotatably mounted on the pivot portion of the housing. Thehub of the impeller has a periphery provided with multiple blades thatare arranged in a radiating manner. A circular fixing frame is mountedon an outer periphery of the blades. The fixing frame has a permanentmagnet. The upper and lower ends of each of the blades are not protrudedfrom the fixing frame.

[0010] Further benefits and advantages of the present invention willbecome apparent after a careful reading of the detailed description withappropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0011]FIG. 1 is an exploded perspective view of a heatsink fan structurein accordance with a first embodiment of the present invention;

[0012]FIG. 2 is a top plan assembly view of the heatsink fan structureas shown in FIG. 1;

[0013]FIG. 3 is a cross-sectional view of the heatsink fan structuretaken along line 3-3 as shown in FIG. 2;

[0014]FIG. 4 is a cross-sectional view of the heatsink fan structuretaken along line 3-3 as shown in FIG. 2 in accordance with a secondembodiment of the present invention;

[0015]FIG. 5 is an exploded perspective view of a heatsink fan structurein accordance with a third embodiment of the present invention;

[0016]FIG. 6 is a top plan assembly view of the heatsink fan structureas shown in FIG. 5;

[0017]FIG. 7 is a cross-sectional view of the heatsink fan structuretaken along line 7-7 as shown in FIG. 6;

[0018]FIG. 8 is an exploded perspective cross-sectional assembly view ofa first conventional heatsink fan structure in accordance with the priorart;

[0019]FIG. 9 is an exploded perspective cross-sectional assembly view ofa second conventional heatsink fan structure in accordance with theprior art; and

[0020]FIG. 10 is a front plan cross-sectional assembly view of theheatsink fan structure as shown in FIG. 9.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Referring to the drawings and initially to FIG. 1, a heatsink fanstructure in accordance with a first embodiment of the present inventioncomprises a housing 1, an outer frame 2, and an impeller 3.

[0022] The housing 1 has a pivot portion 11 for supporting the impeller3 to rotate. The pivot portion 11 may be a central shaft or a centralhole. The pivot portion 11 has a periphery provided with even numbers ofpoles 12. The poles 12 may be energized, to produce a magnetic field anda current direction. The housing 1 may be provided with a circuit boardwhich includes a sensor and other controller, for detecting thevariation of polarity of the permanent magnet 35 of the impeller 3, sothat the poles 12 may change the current direction and produce differentalternating magnetic fields. The housing 1 is provided with combinationmembers 14, such as barbs, and an air outlet 15. The outer frame 2 maybe combined with the combination members 14 of the housing 1, and theair outlet 15 may drive the air flow toward a determined direction.

[0023] The outer frame 2 may be combined with the housing 1. As shown inthe figure, the outer frame 2 may be formed with positioning holes 21for locking the combination members 14 of the housing 1 in a snapmanner. The outer frame 2 has an air inlet 22 which is preferablycircular. The air inlet 22 has a periphery formed with an annular lip23, and the air inlet 22 may be used to introduce the air flow.

[0024] The impeller 3 has a central position formed with a hub 31 whichhas a pivot portion 32 that may be a central shaft or a shaft hole asshown in the figure, so that the pivot portion 32 of the impeller 3 maybe rotatably mounted on the pivot portion 11 of the housing 1. The hub31 of the impeller 3 is provided with multiple blades 33 that arearranged in a radiating manner. A circular fixing frame 34 is mounted onan outer periphery of the blades 33. The circular fixing frame 34 may bemade individually, or integrally formed with the impeller 3. The heightof the circular fixing frame 34 is equal to or greater than that of eachof the blades 33. A permanent magnet 35 is mounted on an outer peripheryof the circular fixing frame 34. At least one of the upper end and thelower end of the inner periphery of the circular fixing frame 34 isformed with a horn-shaped arcuate edge 36 whose maximum diameter isgreater than the diameter of the air inlet 22 of the outer frame 2.

[0025] Referring to FIGS. 2 and 3, the heatsink fan structure inaccordance with the first embodiment of the present invention isassembled. The pivot portion 32 of the impeller 3 is rotatably mountedon the pivot portion 11 of the housing 1. The arcuate edge 36 of theimpeller 3 is opposite to the air inlet 22 of the outer frame 2. Whenthe permanent magnet 35 of the impeller 3 is repulsive with the magneticfield produced by the poles 12 of the housing 1, the impeller 3 may bedriven to rotate. The fixing frame 34 is mounted on the outer peripheryof the blades 33 of the impeller 3, and the maximum diameter of thearcuate edge 36 of the impeller 3 is greater than the diameter of theair inlet 22 of the outer frame 2. Thus, when the impeller 3 is rotated,the driven air flow may be introduced into the air inlet 22 of the outerframe 2, and may be drained outward from the air outlet 15 of thehousing 1. The driven air flow is not in contact with the wall of thehousing 1. Thus, when the impeller 3 is rotated, the driven air flowwill not produce a wind shear problem with the wall of the housing 1,and the noise during rotation of the impeller 3 may be reduced.

[0026] Referring to FIG. 4, a heatsink fan structure in accordance witha second embodiment of the present invention is shown. The lip 23 of theouter frame 2 is formed with an arcuate protruding face 24 extendeddownward. The arcuate protruding face 24 is aligned with the arcuateedge 36 of the impeller 3. Thus, when the impeller 3 is rotated, thedriven air flow may flow more conveniently, and may be drained outwardfrom the air outlet 15.

[0027] Referring to FIG. 5, a heatsink fan structure in accordance witha third embodiment of the present invention comprises a housing 4, andan impeller 5.

[0028] The housing 4 is formed with a receiving space 41 which isprovided with a base board 42 and an air outlet 45. The base board 42 isprovided with a stator seat 43 which has a pivot portion 44 that may bemay be a central shaft or a shaft hole, so that the pivot portion 52 ofthe impeller 5 may be rotatably mounted on the pivot portion 44 of thehousing 1.

[0029] The impeller 5 has a central position formed with a hub 51 whichhas a pivot portion 52 that may be a rotation shaft or a shaft hole, sothat the pivot portion 52 of the impeller 5 may be rotatably mounted onthe pivot portion 44 of the housing 4. The hub 51 of the impeller 5 isprovided with multiple blades 53 that are arranged in a radiatingmanner. A fixing frame 54 is mounted on an outer periphery of the blades53. The height of the fixing frame 54 is greater than that of each ofthe blades 53, so that the upper end and the lower end of each of theblades 53 is not protruded from the fixing frame 54.

[0030] Referring to FIGS. 6 and 7, the heatsink fan structure inaccordance with the third embodiment of the present invention isassembled.

[0031] The pivot portion 52 of the impeller 5 may be rotatably mountedon the pivot portion 44 of the housing 4. The permanent magnet 55 of theimpeller 5 is repulsive with the magnetic field produced by the statorseat 43 of the housing 4, so that the impeller 5 may be driven torotate. The fixing frame 54 is mounted on the outer periphery of theblades 53 of the impeller 5, and the thickness of the fixing frame 54 isgreater than that of each of the blades 54. Thus, when the impeller 5 isrotated, the driven air flow may be introduced into the open space ofthe receiving space 41 of the housing 4, and may be drained outward fromthe air outlet 45 of the housing 4. The driven air flow is not incontact with the wall of the housing 4. Thus, when the impeller 5 isrotated, the driven air flow will not produce a wind shear problem withthe wall of the housing 4, and the noise during rotation of the impeller5 may be reduced.

[0032] Accordingly, in the heatsink fan structure of the presentinvention, the outer periphery of the blades of the impeller is providedwith a fixing frame, and the height of the upper and lower end of theblade is smaller than that of the fixing frame, so that when theimpeller is rotated, the air flow driven by the blades of the impellerwill not be driven sideward from the outer periphery of the blades, andthe air flow and the outer frame or the annular wall of the housing willnot form a wind shear. Thus, the rotation noise of the impeller may bereduced, and rotation of the impeller will produce a larger driven airflow.

[0033] Although the invention has been explained in relation to itspreferred embodiment as mentioned above, it is to be understood thatmany other possible modifications and variations can be made withoutdeparting from the scope of the present invention. It is, therefore,contemplated that the appended claim or claims will cover suchmodifications and variations that fall within the true scope of theinvention.

What is claimed is:
 1. A heatsink fan structure, comprising: a housing,provided with a pivot portion, multiple poles, a circuit board, and anair outlet; an outer frame, combined with the housing, the outer framehaving an air inlet, the air inlet having a periphery formed with anannular lip; and an impeller, having a hub provided with a pivot portionrotatably mounted on the pivot portion of the housing, the hub of theimpeller having a periphery provided with multiple blades that arearranged in a radiating manner, a circular fixing frame mounted on anouter periphery of the blades, the fixing frame having a permanentmagnet, and upper and lower ends of each of the blades being notprotruded from the fixing frame.
 2. The heatsink fan structure asclaimed in claim 1, wherein the fixing frame has a diameter greater thanthat of the air inlet of the outer frame.
 3. The heatsink fan structureas claimed in claim 1, wherein at least one of the upper end and thelower end of the inner periphery of the fixing frame is formed with ahorn-shaped arcuate edge.
 4. The heatsink fan structure as claimed inclaim 3, wherein the lip of the outer frame is extended downward, andhas a curvature the same as that of the arcuate edge of the fixingframe.
 5. A heatsink fan structure, comprising: a housing, having areceiving space provided with a base board and an air outlet, the baseboard provided with a stator seat, the stator seat having a pivotportion; and an impeller, having a hub provided with a pivot portionrotatably mounted on the pivot portion of the housing, the hub having apermanent magnet that is repulsive to a magnetic field produced by thestator seat of the housing, the hub of the impeller having a peripheryprovided with multiple blades, a fixing frame mounted on an outerperiphery of the blades, and upper and lower ends of each of the bladesbeing not protruded from the fixing frame.